The operation of the proposed converter is defined in a number modes of the converter factors i. A fullbridge hardware topology is studied and used to address the basics of the efficient power conversion with high values of power factor. Analysis of acdc converter based on power factor and thd. Load current power in an ac circuit can be given as. Also, applying coupled inductor technique, not only reduces number of the magnetic cores but also with suitable design of coupling coefficient. Unity power factor converter based on a fuzzy controller. On the other hand, under space vector modulation mode the input power factor angle at the rectifier input terminals may lie between. A unity power factor converter using halfbridge boost. Some apc 3phase ups products as well as newer single phase productssrt6k have an output rating of kwkva. In this chapter, we shall discuss the various methods of power factor improvement. Indexing is an important part of journal, indexed content at the article level, also provide doi for the. Comparison and evaluation of power factor correction. However these systems exhibits a low power factor pf, and inject. Impact factor how to publish research paper research paper topics what is doi.
The developments in power factor correction technology in the past two decades have enabled the design and implementation of single phase acdc boost converters with close to unity power factor and much less input current. A unity power factor nibibred converter fed brushless dc motor drive bhim singh, fellow, ieee department of electrical engineering, indian institute of technology delhi, hauz khas, new delhi110016. Power factor corrected single stage acdc full bridge. Sliding mode control of a fullbridge unity power factor rectifier. This practice is known as power factor correction and is achieved by switching in or out banks of inductors or capacitors or by using synchronous generators to create or absorb vars.
This is the most popular ac to dc converter or plainly rectifier filter. Power factor and harmonic analysis in single phase ac to. The controller is designed to drive the converter to operate in continuous conduction mode with near unity power factor with controllable output voltage. The conventional acdc power converters that are connected to the. Power factor in electrical energy management course content what is power factor. Although this appears to be a drawback, realistic value of. This integrated circuit is an active power factor controller specifically used as a pre. Unity power factor control for three phase three level. The generation of harmonics and their subsequent propagation into power lines is a topic of increasing concern to power. Pdf a problem of power factor correction for a class of threephase boost acdc power converters is addressed in this paper.
Benefits of operating your generator at a higher power factor. Power factor is the percentage of electricity that is being used to do useful work. Nearunity power factor, voltage stepupdown conversion. Abstract a singlephase highefficiency nearunity power factor pf halfbridge boost converter circuit, which has been proposed earlier by other researchers. Second, the matrix converter when used with reduced switch count to be used in a rectifier configuration, the simulation results show that a unity power factor and bidirectional power flow are achievable without sophisticated controls and can benefit in v2g operation. The operation for switching mode power supplies smps is to use two separate converter stages, first one having acdc conversion stage and another isolated dcdc conversion stage. Apparent power is the product of the current and voltage of the circuit. As an example, system a in figure 1 shows a typical power system with onsite generation. Phasor diagram of transformer at unity power factor sumit maitra. At zero power factor, the current in coil b is in phase with circuit current, and coil b provides torque to drive the pointer towards 0. Benefits of operating your generator at a higher power factor introduction. A feature of the converters is a significant reduction of conducted electromagnetic interference emi.
What do i gain with a unity output power factor kwkva. A problem of power factor correction for a class of threephase boost acdc power converters is addressed in this paper. That usually occurs when there is no capacitive or inductive reactance in the load or when the reactance has been neutralized. A family of ppfc converters were proposed for different power levels, which are simpler and more efficient than the conventional twocascadestage systems. Power factor and harmonic analysis in single phase ac to dc converter, elect. The developments in power factor correction technology in the past two decades have enabled the design and im plementation of single phase acdc boost converters with close to unity power factor and much less input current distortion that generated by simple diode rectification circuits.
The proposed control is capable of achieving a unity power factor for each dc link voltage or load fluctuation. It is seen that although the displacement power factor is unity, the distortion power factor is high due to large harmonic content resulting in low power factor. Three phase active power factor correction in a single step. A family of low emi unity power factor converters ieee.
Fuzzy logic controlled unity power factor acdc boost converter is constructed and simulated. Aif pfc power factor correction series dcdc converter module enable output ld enable after the pfc power up sequence, the power to the load can be enabled. The use of a unity power factor upf boost preregulator with a following dcdc converter is one of the most popular approaches, for several reasons. The power factor of an ac electric power system is defined as the ratio of the real power to the apparent power, and is a number between 0 and 1. Need for power factor control and harmonic reduction for smps by definition the resistive load is said to have a power factor of one, meaning that 100% of the load current contributes to the watts of power transferred to the load. Grid connected inverter with unity power factor for renewerable energy pv applications. Analysis of acdc converter based on power factor and thd shiney. Practically, it should be as close to unity as possible. Unity power factor control for three phase three level rectifiers without current sensors bingsen wang giri venkataramanan dept. Amakye dickson1 n mensah sitti2 daniel owusu donkor3 nina pearl doe4 ernest a.
The power factor relationship between the current and voltage is given. Acdc converter with unity power factor and minimum harmonic. However, the motors reactive current is circulated between the motor and the inverter bus. Boost converter, unity power factor correction, repetitive control. Fuzzy logic controlled unity power factor converter. The conduction path for this case is illustrated in figure 4. Ncp1607 cost effective power factor controller the ncp1607 is an active power factor controller specifically designed for use as a pre. Remedy for bad power factor it is often possible to adjust the power factor of a system to very near unity.
Traditionally, a ups with a lower power factor needs to be oversized to support todays power factor corrected loads. To achieve constant output voltage and unity power factor at supply mains, sliding mode controller in cascade with the pid voltage loop controller is normally used to control these converters and it is highly evident that the performance. A unity power factor converter with isolation forelectric. Acdc converters, power factor correction, harmonic elimination, active filtering, dualpurpose inverter. A unity power factor nibibred converter fed brushless dc. The advantage of unity power factor is that these ups systems are 100% compatible with todays high power factor loads. Voltage regulation of transformer at unity power factor. The only limitations in the designs are the power converter ratings. Abstract this paper analyses the low power factor and harmonic issues in ac to dc converters i. Unity power factor control in threephase acdc boost converter using sliding modes article pdf available in ieee transactions on industrial electronics 5511. Vashist bist, student member, ieee department of electrical engineering, indian institute of technology delhi. Unity power factor converter based on a fuzzy controller and predictive input current.
This can be performed manually or the pfc can automatically enable the load using the ld enable signal. Josephs college of engineering and technology, palai, india1. The paper describes some important design considerations in developing a variable threephase acdc converter with unity power factor and the minimum. In this way, this isolated pfc converter makes the input current sinusoidal in structure and improves input power factor to unity. In active power factor correction, a power electronic converter is used in conjunction with the diode bridge rectifier and output capacitor for current waveform shaping. Bidirectional acdc matrix converter with unity power factor. A new family of softswitching unity power factor converters with high input power factor and isolated output is presented. A two switch threephase power factor correction sepic converter with coupled inductor operating in discontinuous current mode is presented. On the other hand, using a parallel configuration, a power factor cor rection topology, usually an active filter is placed in.
A unity power factor converter using halfbridge boost topology abstract. Input power factor an overview sciencedirect topics. The power factor of the total current supplied to the distribution board is monitored by a controller which then switches capacitor banks in a fashion to maintain a power factor better than a preset limit. Highfrequencyfed unity power factor ac dc power converter with one switching per cycle. A repetitivepi current controller for boost single phase. If the boost converter is operated in dcm, an input power factor close to unity is obtained, provided that the output voltage is about twice the peak input voltage 25. We hope to give you an easy explanation of what power factor is, and to answer. This is followed by the capacitor and may be a bleeder resistance and goes to further loads. Unity power factor converters will just be mentioned in this lectur e but there is a vast literature about them see, for example, refs.
Grid connected inverter with unity power factor for. This converter is capable of operating under variable pf. In an ideal world all loads would have power factor of unity. Abstract a singlephase highefficiency nearunity power factor pf half bridge boost converter circuit, which has been proposed earlier by other researchers. It is defined as the ratio of active or actual power used in the circuit measured in watts or kilowatts w or. Unity power factor and tight output voltage regulation are achieved with the. Power factor is the latest parameter to receive attention, with the emergence of unity and linear power factor ups systems. Singlestage nearunity power factor acdc converter with both. A singlephase highefficiency nearunity powerfactor pf halfbridge boost converter circuit, which has been proposed earlier by other researchers, is presented with detailed analysis. Unity power factor exists in an ac circuit when the angle between the voltage and the current is zero. The output may have an inductive lagging power factor, due to the motors inductive reactance.
Six converter topologies have been identified that share a zerovoltageswitching zvs phase arm on the input boost converter stage. Unity power factor threephase acdc converter applying. Traditionally, ac to dc conversion is achieved using threephase diode bridge rectifiers 1. High frequency fed unity power factor acdc converter for wireless power transfer applications rose maria alex1, ginu ann george2 pg scholar, dept of electrical and electronics engg, st. An efficient unity power factor battery chargingdischarging unit abstract rechargeable battery is considered to be one of the main electric energy storage devices. Due to the problem of posible shortage of energy resources, cost or enviromental cosiderations, a power saving and energy efficient devices.
A study on input power factor compensation capability of. Dcm discontinuous conduction mode or ccm continuous conduction mode alongside with the best plan equations. On a socalled pwm pulse width modulated drive with a diode bridge converter input, the power factor to the ac line is near unity see fig. Introduction the energy efficiency and power transfer capability of a poor pf system are relatively low because of the high conduction loss in the power converters and transmission wires. Benefits of doi journal indexing open access journal. There are numerous approaches to power factor enhancement, of varying complexity, cost and effectiveness.
The switches voltage stress in this converter is related to peak of phase voltage instead of line voltage. Unity power factor, hybrid switching control, three phase converter, fpga. If power factor is low, following problems are encountered. High frequency fed unity power factor acdc converter for.
Phasor diagram of transformer at leading power factor condition duration. Real power is the capacity of the circuit for performing work in a particular time. There is no problem with bulk correction operating at unity. Recently a singlestage acdc converter configuration which combines a boost power factor correction pfc circuit with a twotransistor dcdc converter is. Data centres and it equipment in general are becoming increasingly power hungry as processing speed increases, so the need for greater efficiency of power equipment is paramount. At unity power factor, the current in a is in phase with the circuit current, and coil a provides maximum torque, driving the instrument pointer toward the 1.
Moreover, with continuous input current, the diodes of the bridge can be. Slidingmode control for a threephase unity power factor. Therefore, we need acdc converter is the one that draws a pure sinusoidal current at unity power factor from the mains. The method under study is composed of two intelligent approaches, a fuzzy logic controller to ensure an output voltage at a suitable value and. Pdf unity power factor control in threephase acdc boost. Phasor diagram of transformer at unity power factor youtube.